What happens if it's extremely hot?

Question

Accepted Answer

The ITF Supervisor measures the Wet-Bulb Globe Temperature (WBGT) on court at least three times a day (30 minutes before play, mid-day and before the last match), or the Heat Index if WBGT can't be measured.

Condition	WBGT	Heat Index
Modification of play	30.1°C or more	34.0°C or more
Suspension of play	32.2°C or more	40.1°C or more

When modification applies:

In a best-of-three tie-break sets match, a 10-minute break is allowed between the second and third sets if any player asks for it.
No coaching is allowed during that break.
The Supervisor may also delay match starts until conditions improve.

At the suspension level, play is suspended. The Supervisor can also apply these procedures at lower readings if needed for player safety.